Hydroxymethylfurfural Reduction Methods and Methods of Producing Furandimethanol

ABSTRACT

A method of reducing hydroxymethylfurfural (HMF) where a starting material containing HMF in a solvent comprising water is provided. H 2  is provided into the reactor and the starting material is contacted with a catalyst containing at least one metal selected from Ni, Co, Cu, Pd, Pt, Ru, Ir, Re and Rh, at a temperature of less than or equal to 250° C. A method of hydrogenating HMF includes providing an aqueous solution containing HMF and fructose. H 2  and a hydrogenation catalyst are provided. The HMF is selectively hydrogenated relative to the fructose at a temperature at or above 30° C. A method of producing tetrahydrofuran dimethanol (THFDM) includes providing a continuous flow reactor having first and second catalysts and providing a feed comprising HMF into the reactor. The feed is contacted with the first catalyst to produce furan dimethanol (FDM) which is contacted with the second catalyst to produce THFDM.

RELATED PATENT DATA

This patent claims priority under 35 U.S.C. §119 to U.S. ProvisionalApplication No. 60/804,409, which was filed Jun. 9, 2006.

TECHNICAL FIELD

The invention pertains to hydroxymethylfurfural reduction methods,methods of producing furandimethanol, and methods of producingtetrahydrofuran dimethanol.

BACKGROUND OF THE INVENTION

Hydroxymethylfurfural (HMF) is a compound which can be produced fromvarious hexoses or hexose-comprising materials. HMF can in turn beconverted into a variety of derivatives, many of which are currently orare quickly becoming commercially valuable. Of particular interest is areduction product furandimethanol (FDM). Another reduction product ofinterest is tetrahydrofuran dimethanol (THF dimethanol, alternativelyreferred to as THF-diol or THFDM). FDM and THF dimethanol are useful inadhesives, sealants, composites, coatings, binders, foams, curatives,polymer materials, solvents, resins or as monomers, for example.

Conventional methodology for production of FDM and/or THF dimethanolfrom HMF typically results in low yields, and/or low selectivity and cantherefore be cost prohibitive. Additionally, conventional methodologyoften utilizes one or more environmentally unfriendly compound orsolvent, or utilizes harsh reaction conditions. Accordingly, it isdesirable to develop alternative methods for production of FDM and/orTHF dimethanol from HMF.

SUMMARY OF THE INVENTION

In one aspect the invention encompasses a method of reducing HMF where astarting material containing HMF in a solvent comprising water isprovided into a reactor. H₂ is provided into a reactor and the startingmaterial is contacted with a catalyst containing at least one metalselected from Ni, Co, Cu, Pd, Pt, Ru, Ir, Re and Rh. The contacting isconducted at a reactor temperature of less than or equal to 250° C.

In one aspect the invention encompasses a method of hydrogenating HMF.An aqueous solution containing HMF and fructose is provided into areactor and H₂ is provided into the reactor. A hydrogenation catalyst isprovided in the reactor. The HMF is selectively hydrogenated relative tothe fructose at a temperature at or above about 30° C.

In one aspect the invention pertains to a method of producingtetrahydrofuran dimethanol (THFDM) A feed comprising HMF is providedinto a reactor containing a first and a second catalyst. The feed iscontacted with the first catalyst to produce furan dimethanol (FDM). TheFDM is contacted with the second catalyst to produce THFDM.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 shows conversion of HMF and selective production offurandimethanol and tetrahydrofuran diol (THF diol) as a function oftime on stream (TOS) utilizing a continuous flow reactor with a cobaltsupported on SiO₂ catalyst and a base set of parameters in accordancewith one aspect of the invention.

FIG. 2 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at an increased liquidhourly space velocity (LHSV) relative to FIG. 1.

FIG. 3 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at a decreased pressurerelative to FIG. 1.

FIG. 4 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at a decreasedtemperature relative to FIG. 1.

FIG. 5 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at a decreasedtemperature relative to FIG. 1.

FIG. 6 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at a decreased pressurerelative to that of FIG. 1.

FIG. 7 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at decreased pressureand temperature relative to that of FIG. 1.

FIG. 8 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 and an increased HMFfeed concentration relative to that of FIG. 1.

FIG. 9 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at an increased HMF feedconcentration and decreased pressure relative to that of FIG. 1.

FIG. 10 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at an increased HMF feedconcentration and a decreased pressure with increased temperaturerelative to that of FIG. 1.

FIG. 11 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at an increasedtemperature relative to FIG. 1.

FIG. 12 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 1 at an increased pressurerelative to that of FIG. 1.

FIG. 13 shows HMF conversion and product selectivity as a function oftemperature utilizing the catalyst of FIG. 1.

FIG. 14 shows HMF conversion and product selectivity as a function ofpressure utilizing the catalyst of FIG. 1.

FIG. 15 shows HMF conversion and product selectivity as a function oftime on stream utilizing an 0.8% palladium supported on carbon catalystin a continuous flow reactor utilizing a base set of reaction parametersin accordance with one aspect of the invention.

FIG. 16 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 15 at a decreased LHSVrelative to FIG. 15.

FIG. 17 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 15 at an increasedtemperature and decreased LHSV relative to FIG. 15.

FIG. 18 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 15 at an increasedpressure and decreased LHSV relative to FIG. 15.

FIG. 19 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 15 at reduced pressure andincreased temperature and decreased LHSV relative to FIG. 15.

FIG. 20 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 15 at an increased temperatureand decreased LHSV relative to FIG. 15.

FIG. 21 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 15 at a decreased H₂ gas hourlyspace velocity (GHSV), increased temperature, and decreased LHSVrelative to FIG. 15.

FIG. 22 shows HMF conversion and product selectivity as a function oftime on stream for a continuous flow reactor utilizing a Pt on SiO₂support (in-house prep) catalyst and a base set of reaction parametersin accordance with one aspect of the invention.

FIG. 23 shows HMF conversion and product selectivity as a function oftime on stream for a continuous flow reaction utilizing another Co/SiO₂catalyst and a base set of reaction of parameters in accordance withanother aspect of the invention.

FIG. 24 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 23 at a decreased pressureand decreased temperature relative to FIG. 23.

FIG. 25 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 23 at a decreased pressureand decreased temperature with an increased HMF feed concentrationrelative to FIG. 23.

FIG. 26 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 at an increased temperaturerelative to FIG. 23.

FIG. 27 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 at the parameters used inFIG. 23.

FIG. 28 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 utilizing an increased LHSVrelative to FIG. 23.

FIG. 29 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 utilizing an increased HMFfeed concentration relative to FIG. 23.

FIG. 30 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 23 and the parameters ofFIG. 23 where the catalyst was pretreated by dry reduction at 150° C.

FIG. 31 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 after 150° C. dry reductionutilizing the parameters of FIG. 23.

FIG. 32 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 reduced at 150° C. at adecreased LHSV.

FIG. 33 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 reduced at 150° C. at adecreased LHSV relative to FIG. 23.

FIG. 34 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 reduced at 150° C. at anincreased reactor temperature relative to FIG. 23.

FIG. 35 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 reduced at 230° C.

FIG. 36 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 originally reduced at 230° C.utilizing a decreased LHSV relative to FIG. 23.

FIG. 37 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 reduced at a temperature of362° C.

FIG. 38 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 23 originally reduced at 362° C.

FIG. 39 shows HMF conversion and product selectivity as a function oftime on stream utilizing a Cu—Cr catalyst and a base set of reactionparameters in accordance with another aspect of the invention.

FIG. 40 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 39 and an increased LHSVrelative to FIG. 39.

FIG. 41 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 39 at an increased HMF feedconcentration relative to FIG. 39.

FIG. 42 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 39 at an increased LHSV over aportion of the run and N₂ sparging.

FIG. 43 shows HMF conversion and product selectivity as a function oftime on stream for a 5% Pt/Al₂O₃ catalyst reduced at 150° C. at a baseset of reaction parameters with varied LHSV.

FIG. 44 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 43 originally reduced at 150° C.at a decreased LHSV relative to FIG. 43.

FIG. 45 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 43 and a crude HMF feed.

FIG. 46 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 43 and a second crude HMFfeed.

FIG. 47 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 43 and a third crude HMFfeed.

FIG. 48 shows HMF conversion and product selectivity as a function oftime on stream utilizing the catalyst of FIG. 43 at an increased reactortemperature relative to FIG. 43.

FIG. 49 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 43 at an increased reactortemperature and at an increased LHSV relative to FIG. 43.

FIG. 50 shows HMF conversion and product selectivity as a function oftime on stream of the catalyst of FIG. 43 at an increased reactortemperature and increased LHSV relative to FIG. 43.

FIG. 51 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 43 at an increased reactortemperature and at an increased LHSV relative to FIG. 43.

FIG. 52 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 43 at an increased pressure anddecreased LHSV relative to FIG. 43.

FIG. 53 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 43 at an increased pressure, anincreased temperature and at an increased LHSV relative to FIG. 43.

FIG. 54 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 43 at an increased pressure, anincreased temperature and at an increased LHSV relative to FIG. 43.

FIG. 55 shows HMF conversion and product selectivity as a function oftime on stream for the catalyst of FIG. 43 at a decreased pressure anddecreased LHSV relative to FIG. 43.

FIG. 56 shows HMF conversion and product selectivity as a function oftemperature for the catalyst of FIG. 43.

FIG. 57 shows HMF conversion and product selectivity as a function oftime on stream utilizing a continuous flow reactor and a Co/SiO₂catalyst at 120° C.

FIG. 58 shows FDM conversion and product selectivity as a function oftime on stream for a continuous flow reactor utilizing a Ni/SiO₂catalyst at 70° C.

FIG. 59 shows HMF conversion and product selectivity as a function oftime on stream for a continuous flow reactor utilizing a Ni/SiO₂catalyst at 70° C. at varied LHSV.

FIG. 60 shows a repeat of FDM conversion and product selectivity as afunction of time on stream for a continuous flow reactor utilizing aNi/SiO₂ catalyst at 70° C., after the run shown in FIG. 59.

FIG. 61 shows HMF conversion and product selectivity for a staged bed(segregated catalysts) continuous flow reactor utilizing Co/SiO₂ andNi/SiO₂ catalysts.

FIG. 62 shows HMF conversion as a function of time on stream for astaged bed continuous flow reactor utilizing segregated Co/SiO₂ andNi/SiO₂ catalysts and a base set of reaction conditions in accordancewith one aspect of the invention.

FIG. 63 shows HMF conversion as a function of time on stream utilizingthe system of FIG. 62 and increased temperatures relative to FIG. 62.

FIG. 64 shows HMF conversion as a function of time on stream utilizingthe system of FIG. 62 and increased feed concentration and increasedLHSV relative to FIG. 62.

FIG. 65 shows HMF conversion as a function of time on stream utilizingthe system of FIG. 62 with increased feed concentration and decreasedLHSV relative to FIG. 62.

FIG. 66 shows HMF conversion as a function of time on stream utilizingthe system of FIG. 62 with increased temperatures and decreased LHSVrelative to FIG. 62.

FIG. 67 shows HMF conversion as a function of time on stream utilizingthe system of FIG. 62 with increased temperature and decreased LHSVrelative to FIG. 62.

FIG. 68 shows tetrahyrofuran dimethanol (THFDM) conversion as a functionof time on stream utilizing the system of FIG. 62 and increasedtemperature with decreased LHSV relative to FIG. 62.

FIG. 69 shows THFDM conversion as a function of time on stream utilizingthe system of FIG. 62 and increased temperature with decreased LHSVrelative to FIG. 62.

FIG. 70 shows HMF or FDM conversion as a function of time on streamutilizing the system of FIG. 62 and increased temperature with decreasedLHSV relative to FIG. 62.

FIG. 71 shows HMF conversion and product selectivity as a function ofreaction time for a batch reaction utilizing RANEY® cobalt (Cr—Ni—Fe).

FIG. 72 shows HMF conversion and product selectivity as a function ofreaction time for a batch reactor utilizing 5% Pt (Ge)/C catalyst.

FIG. 73 shows HMF conversion and product selectivity as a function ofreaction time for a batch reactor utilizing a 5% Pd/C catalyst.

FIG. 74 shows HMF conversion and product selectivity as a function ofreaction time for a batch reactor utilizing a 5% Ru/C catalyst.

FIG. 75 shows HMF conversion and product selectivity as a function ofreaction time for a batch reactor utilizing a RANEY® cobalt catalyst at60° C.

FIG. 76 shows HMF conversion and product selectivity as a function ofreaction time for the catalyst of FIG. 75 at an increased temperaturerelative to FIG. 75.

FIG. 77 shows HMF conversion and product selectivity as a function ofreaction time for a batch reactor utilizing a RANEY® copper spongecatalyst.

FIG. 78 shows HMF conversion and product selectivity as a function ofreaction time at two different reactor pressures for a batch reactorutilizing 5% Pt (Ge)/C catalyst.

FIG. 79 shows HMF conversion as a function of reaction time at threedifferent temperatures utilizing a 5% Pt (Ge)/C catalyst.

FIG. 80 shows FDM product selectivity as a function of reaction time atthree different temperatures utilizing the 5% Pt (Ge)/C catalyst of FIG.79.

The following acronyms are used:

FDM=Furan-2,5-dimethanol; GHSV=Gas hourly space velocity;12HD=1,2-hexanediol; HMF=5-Hydroxymethyl-2-furaldehyde;HMFCA=5-Hydroxymethyl-2-furancarboxylic acid; LHSV=Liquid hourly spacevelocity; THFA=Tetrahydrofurfuryl alcohol;THF-diol=Tetrahydrofuran-2,5-dimethanol (THFDM);THFDM=Tetrahydrofuran-2,5-dimethanol (THF-diol);1,2,6-THH=1,2,6-trihydroxyhexane; 1,2,6-Triol=1,2,6-trihydroxyhexane;TOS=Time on Stream

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

In general, the methodology of the invention encompasses production offurandimethanol (FDM), production of tetrahydrofuran dimethanol (THFdimethanol), or both. More specifically, selective reduction of thealdehyde group on HMF, or both aldehyde groups on alternative startingmaterial diformyl furan (DFF), can be conducted to selectively produceFDM. In particular instances, THF dimethanol is produced as a byproduct.Alternatively, reaction parameters and/or the reaction catalyst can bealtered to increase production of, or to selectively produce THFdimethanol. The reaction methodology involves providing HMF or DFF inaqueous solution or within an aqueous mixture. However, the inventioncontemplates conducting reduction reactions in the presence of one ormore organic solvents. In general, the reaction mixture is exposed to acatalyst in accordance with the invention which promotes a reduction ofthe aldehyde group, and in particular instances the carbon-carbon doublebond(s), in water solvent and under relatively mild reaction conditionsas compared to conventional methodology. It is to be understood that theinvention additionally includes use of alternative starting compoundsfor reduction utilizing methodology in accordance with the invention,such as HMF derivatives with similarly reducible groups including butnot limited to formyl, acid, ester or amide groups.

For aqueous reactions, the relatively mild reaction conditions ofreduction methodology in accordance with the invention typicallycomprise a reaction temperature of less than or equal to 250° C., and inparticular instances the reaction temperature will be less than or equalto 100° C. The reduction reaction is performed in the presence of H₂.Typically the H₂ pressure will be at least 1 atm (14.7 psi) and lessthan or equal to 1400 psi, more typically between 200-500 psi. Althoughnot limited to a particular pH, the HMF reduction is typically conductedat a pH of about neutral.

For methodology of the invention that utilize fixed-bed continuous flowoperation, additional parameters such as liquid and gas flow rates, andfeed concentration can be adjusted and in some aspects can affectoverall yield.

In one aspect, catalysts of the present invention can comprise at leastone of the catalyst metals selected from the group consisting of Pd, Pt,Ru, Rh, Ni, Ir, Cu, Re and Co. In particular instances, catalystscomprising Pd, Pt, Co, Rh, Ir, Cu and/or Ni, can be combinationcatalysts which additionally include one or more metals selected fromthe group consisting of Ca, Cr, Mn, Re, Fe, Ru, Rh, Ir, Ni, Pd, Pt, Ag,Au, In, Ge, Cu, Sn, S, Cd, Ga, Al, Mo, Zn and Bi. In particularembodiments, the catalyst can preferably comprise both In and Ir. Inalternative aspects, a Cu-chromite catalyst can be preferred.

Where catalysts comprising these metals or combinations of metals areutilized for HMF/HMF-derivative reduction, the catalyst metal cantypically be supported by one or more support materials. Such supportmaterials can be, for example, carbon support materials including butnot limited to activated carbon support materials, and various inorganicsupports such as metal oxide support materials including but not limitedto Zr-oxides, Ti-oxides, Al-oxides, Si-oxides, etc. Various exemplarycatalysts of the type described above which were utilized for conductingreduction methodology in accordance with the invention are set forth inTables 1 and 2. Table 1 presents commercially available catalysts whileTable 2 presents catalysts prepared in-house for use in the reductionreactions. It is to be understood that the listed catalysts areexemplary and are not intended to limit the scope of the invention.

TABLE 1 Exemplary commercially available catalysts for HMF reductionCatalyst Composition Manufacturer Lot No/Sample ID 5% Pd, 0.5% Cu/CEngelhard 787A-15-409-1 10%/Pd/C Degussa CC1-2155 5% Pd, 1% Sn/CEngelhard SOC 98186 5% Pd, 0.15% Fe/C Engelhard 787A-8-157-1 5% Pd, 0.5%Fe/C Engelhard 787A-15-417-1 5% Pd/C Engelhard 39658 5% Pd, 5% Re/CEngelhard 6758-17-03 5% Pd, 5% Re/C Engelhard 6555-38-1 5% Pt(Ge)/CEngelhard 43932 5% Pt(S)/C Engelhard 787A-15-321-1 1.5% Pt, 0.15% Cu/CEngelhard 787A-8-153-1 1.5% Pt, 0.15% Sn/C Engelhard 787A-8-152-1 1.5%Pt, 0.15% Bi/C Engelhard 787A-8-151-1 1.5% Pt, 0.15% Ru/C Engelhard787A-8-150-1 3% Pt/Al₂O₃ Engelhard 6849-14-1 3% Pt/C Engelhard 43931Escat 288 Engelhard 324230 5% Ru/C AlfaAesar C10J23 2.5% Ru/C Engelhard6818-13-2 5% Ru/ZrO₂ Engelhard 712A-4-294-1 5% Ru/C Johnson Matthey072183 3% Ru/TiO₂ (rutile) Degussa H7709x/o 3% Ru/TiO₂ Degussa CC4-251A5% Rh/C Heraeus K-0319 5% Rh/C Engelhard 43671 Ni powder MallinckrodtS-96-674 2.5% Ni, 2.5% Re/C Engelhard 6757-43-2 4% Ni, 4% Re/C Engelhard6818-15-3 Cu/Or SudChemie G-22/2 Cu/Cr/Mn United Catalyst G-89, 4171-S(SudChemie) Cu-chromite Engelhard S-02-245 1.5% Pt, 0.15% Cu on CEngelhard 787a-8-153-1 10% Re on Al₂O₃ Davicat Al2301 10% Re on Al₂O₃Davicat Al2400 0.5% Pd on C Degussa E181 5% Rh on C Degussa G106 5% Ruon ZrO₂ Engelhard Ru on ZrO₂ 0.7% Ru on C Engelhard 47038 5% Pd, 1% Snon C Engelhard 5% Pd 1% Sn 2.5% Ni, 2.5% Re on C Engelhard 6757-43-2 5%Pd, 5% Re on C Engelhard 6758-17-02 2.5% Co, 2.5% Re on C Engelhard6818-15-1 2% Ni, 2.5% Re on C Engelhard 6818-20-4 Supported 40% CoEngelhard Co-0124 Supported 40% Co Engelhard Co-0138 Supported 40% CoEngelhard Co-0164 40% Co on SiO₂ Engelhard Co-0179 Supported 50% NiEngelhard Ni-3210 T Supported 50% Ni Engelhard Ni-3288 E Supported CuEngelhard Cu-1186 t 1/8 lot #60″ 0.8% Pd on C Engelhard Escat 132 0.5%Pd on C Engelhard Escat 138 0.5% Pt on C Engelhard Escat 238 5% Pt on CEngelhard Escat 288 Supported Cu Sud Chemie G-132 1/16 ext.″ SupportedCu Girdler G-9 CuMn tab. Supported Cu Harshaw Cu-2501 G4-6 5% Rh on CEngelhard Italiana 43664 Supported Cu Katalco ICI MeOH cat. CuZnAl 55%Ni on SiO₂ Sud Chemie C46-7-03 RS 40% Co on SiO₂ + ZrO₂ Sud ChemieG62aExt 40% Co on SiO₂ Sud Chemie G62aRS 40% Co on SiO₂ + ZrO₂ SudChemie G67aRS Ext Supported 50% Ni Sud Chemie G69bRS Supported Cu SudChemie G-99b-13 EF tab. Supported Cu Sud Chemie T-4489 rs 3 × 3 tab 40%Co on SiO₂ United Catalysts G62RS Supported Cu United Catalysts G-89CuCrMn Supported Cu United Catalysts T-4489 CuAl Raney  ® 2700-Co W.R.Grace & Co Lot# 7865 Raney  ® 2724-Co W.R. Grace & Co Lot# 8318 Raney  ®Cu sponge Strem Chemicals Lot# 141625-S Raney  ® Ni catalyst ActivatedMetals A-5200

TABLE 2 Reduction catalysts prepared in-house. Catalyst CompositionCatalyst Composition 5% Co on SiO₂ 5.1% Ir on SiO₂ 20% Co on SiO₂ 2.6%Ir, 0.3% Ca on SiO₂ 5% Co, 1% Ag on SiO₂ 2.6% Ir, 0.7% Cd on SiO₂ 20%Co, 4% Ag on SiO₂ 2.6% Ir, 0.5% Ga on SiO₂ 5% Co, 1.8% Au on SiO₂ 2.6%Ir, 0.8% In on SiO₂ 20% Co, 7.2% Au on SiO₂ 2.6% Ir, 0.8% Sn on SiO₂ 5%Co, 0.4% Ca on SiO₂ 7% Ni, 0.5% Fe on C 20% Co, 1.6% Ca on SiO₂Supported 20% Ni, 10% Mo 5% Co, 0.6% Cu on SiO₂ 1% Pd on TiO₂ (rutile)20% Co, 2.4% Cu on SiO₂ 1.4% Pd on SiO₂ 5% Co, 0.3% Fe on SiO₂ 1.4% Pd,0.3% Ca on SiO₂ 20% Co, 1.2% Fe on SiO₂ 1.4% Pd, 0.7% Cd on SiO₂ 5% Co,0.9% Ir on SiO₂ Pd, Fe on C 20% Co, 3.5% Ir on SiO₂ 1.4% Pd, 0.5% Ga onSiO₂ 5% Co, 0.3% Mn on SiO₂ 1.4% Pd, 0.8% In on SiO₂ 20% Co, 1.2% Mn onSiO₂ 1.4% Pd, 0.8% Sn on SiO₂ 5% Co, 0.3% Ni on SiO₂ Pt on C 20% Co,1.2% Ni on SiO₂ 2.6% Pt on SiO₂ 5% Co, 0.5% Pd on SiO₂ 5% Pt on SiO₂ 20%Co, 2% Pd on SiO₂ 5% Pt on Al₂O₃ 5% Co, 0.9% Pt on SiO₂ 2.6% Pt, 0.3% Caon SiO₂ 20% Co, 3.5% Pt on SiO₂ 2.6% Pt, 0.7% Cd on SiO₂ 5% Co, 0.5% Rhon SiO₂ 2.6% Pt, 0.5% Ga on SiO₂ 20% Co, 2% Rh on SiO₂ 2.6% Pt, 0.8% Inon SiO₂ 0.65% Ir on SiO₂ 2.6% Pt, 0.8% Sn on SiO₂ 1.3% Ir on SiO₂ 1.4%Rh on SiO₂ 2.6% Ir on SiO₂ 1.4% Rh, 0.8% In on SiO₂ 5.1% Ir on SiO₂ 1.4%Rh, 0.8% Sn on SiO₂

For preparation of the catalysts presented in Table 2, support materialwas manually weighed into a vial, impregnated with the first metalsolution and allowed to dry in air at ambient pressure overnight. Wherea second metal was utilized, a second metal solution was then added.Optionally, the vial could be exposed to a flow of air (100 mL/min) andheated to 400° C. for 4 h with a ramp of about 5° C./min. The vial wasthen placed in a catalyst reduction reactor and reduced at 250-300° C.with a ramp of 1-2° C./min and held for 2-4 h under a flow of H₂ (100mL/min). After reduction, the catalyst reduction reactor was sealedunder an N₂ environment and moved to a glovebox where the catalyst couldbe loaded into the conversion reactor.

Each of the catalysts listed in Tables 1 and 2 was tested batch-wiseunder mild conditions (typical conditions: 500 psi H₂ and 60° C. for areaction time of 1 hour) and/or in a fixed-bed continuous flow reactor.Of the listed catalysts tested batch-wise, Co, Pd, Ir and Pt catalystsresulted in the highest yields of FDM. Test reactions were alsoconducted batch wise at temperatures as low as 30° C. and showed goodconversion of HMF. The batch testing additionally included experimentsconducted as low as 100 psi H₂, also showing good conversion.Selectivity of HMF to FDM is often highest upon just reachingapproximately 100% conversion of HMF, with continued reaction timessometimes resulting in over-reduction.

Reactions were also performed utilizing various of the catalystspresented in the Tables in fixed-bed reactor systems. Such studiessuggest that, of the catalysts tested, Pd, Pt, Co and Cu—Cr catalystscan be preferred for FDM production under the conditions utilized.

In addition to the catalysts described above, reaction methodology ofthe invention can alternatively be conducted utilizing RANEY® typemetals such as RANEY® nickel, RANEY® cobalt or RANEY® copper.

With respect to the RANEY® type metals, RANEY® cobalt appears to be bothhighly active and selective for FDM production from HMF. RANEY® Ni isalso able to catalyze reduction of HMF to FDM under the reactionconditions of the present invention. RANEY® copper also shows ability toproduce FDM under the mild reaction conditions, however such metal isless reactive and gives a different product distribution than wasobserved for RANEY® cobalt or RANEY® Ni catalyzed reductions.

Example 1 Selective Reduction of HMF Utilizing Pd/C

To 10 mL of water in a small pressure autoclave (45 mL total volume) wasadded 0.2289 g of dry Pd/C catalyst (commercially available 0.8% Pd oncarbon). A magnetic stir bar was added and the vessel was sealed. Thereactor was purged with N₂ and was pressure tested for leaks at 500 psi.After confirming an absence of leaks, the vessel was vented, the linewas removed and 0.4513 g of HMF dissolved in 5 mL of water was addedutilizing a small syringe and needle through the 1/16 inch fitting onthe head of the vessel.

The vessel was then purged with N₂, purged with H₂ and pressurized to500 psi H₂. The reaction vessel was isolated from the H₂ feed line by avalve downstream from the pressure gauge. The reactor was brought to areaction temperature of 60° C. in less than 5 minutes. After 2 hoursreaction time (measured from the point of reaching 60° C.) the pressurewithin the vessel was determined to be 330 psi. The vessel was thenvented and purged with N₂ and the gas line removed to allow sampling ofvessel contents. Approximately 1 mL of sample was removed utilizing anapproximately 5 inch needle, and the sample was filtered utilizing a 0.2micron syringe filter. The gas line was then reconnected and the vesselpurged with N₂ followed by H₂ and was re-pressurized to 500 psi H₂.

Sampling was repeated after 4 hours and the reaction was stopped afterremoving the 4 hour sample. Each of the 2 hour and 4 hour samples wasdiluted by 50% and was analyzed by liquid chromatography (LC). Theresults showed that by 2 hours the HMF conversion was 100% with 51%selectivity to FDM due to over-reduction (as apparent by the presence ofTHF dimethanol).

Example 2 Reduction of HMF Utilizing RANEY® Metals

Reduction reactions were performed utilizing RANEY® cobalt, RANEY®copper and RANEY® nickel in independent reactions. The reductionreactions were performed at 60° C. and 500 psi H₂ for at least 2 hours.The experiment conducted utilizing RANEY® cobalt resulted in a 100% HMFconversion with 97% selectivity for FDM upon reacting for 2 hours. Asindicated above, RANEY® copper was less reactive and resulted in adifferent product distribution.

Example 3 Reduction of HMF with Production of THF Dimethanol

A commercially available nickel powder catalyst (Mallinckrodt SpecialtyChemical Company, Calsicat, S-96-674, #69F-093A, E-473P L, 12/6/96) wasutilized. The catalyst was received and stored under water.

1 mL of catalyst slurry was placed in a glass liner and 9 mL of wateradded. A magnetic stir bar was added and the liner sealed in a 45 mLautoclave. The autoclave was purged and pressure/leak tested to 500 psiwith hydrogen. The autoclave was vented and 0.45 grams of HMF dissolvedin 5 mL of water was added. The reactor was purged again, andpressurized to 500 psi with hydrogen. The desired temperature of 60° C.was achieved upon heating for approximately 5 minutes and was maintainedfor 2 hours at which time the first sample was removed and analyzed byLC. HMF conversion was 99% with selectivity to FDM of 84%. Overreduction of FDM to THF dimethanol occurred with a selectivity to THFdimethanol of 10%.

After 4 hours at 60° C. a second sample was removed and analyzed.Conversion of HMF was 100% with more over reduction, selectivity to FDMdropped to 77% and selectivity to THF dimethanol increased to 17%. At 4hours the temperature was increased to 100° C. and pressure increased to950 psi hydrogen. After 3 hours of additional reaction under theseconditions, FDM selectivity had dropped to 3% and THF dimethanolselectivity increased to 95%.

In fixed-bed continuous flow experiments using the same or similarcatalysts and reaction conditions described above, alternativeparameters such as gas and liquid flow rates, and feed concentrationswere also independently varied to study the effect of such variations onconversion, yield and selectivity. A first set of studies was performedutilizing cobalt metal on SiO₂ support material with varying parametersincluding temperature, H₂ pressure, feed concentration, and flow rateparameters. The results of such studies are presented in a series ofgraphs set forth in FIGS. 1-14.

Similar studies were performed utilizing a palladium metal on carbonsupport catalyst. For both the palladium and the cobalt catalyststudies, a fixed-bed reactor was utilized to allow sample flow rate tobe studied. The results of independent variants of flow rate, reactiontemperature, and pressure for the Pd/C catalyst studies are presented inFIGS. 15-21. Tables 3 and 4 show the effect of pressure at 70° C. and100° C. respectively utilizing the Pd/C catalyst.

TABLE 3 Pressure Effect (T = 70° C., data taken at TOS = 60 minutes) P =500 psig P = 800 psig HMFConv, wt % 57.29 51.71 FDM Sel, wt % 88.3684.07 THF Diol Sel, wt %  3.78  5.68 Sel to Others, wt %  7.86 10.25

TABLE 4 Pressure Effect (T = 100° C., data taken at TOS = 60 minutes) P= 200 psig P = 500 psig HMFConv, wt % 72.68 95.32 FDM Sel, wt % 91.1987.93 THF Diol Sel, wt %  1.28  4.79 Sel to Others, wt %  7.53  7.28

Additional flow reactor studies were conducted utilizing alternativecatalysts. Presented herewith are results of flow reactor studiesconducted utilizing Pt/SiO₂ (FIG. 22), an alternative Co/SiO₂ catalyst(FIGS. 23-38), a copper-chromite catalyst (FIGS. 39-42), or Pt/Al₂O₃(FIGS. 43-56). The enclosed sets of results for the alternative Co/SiO₂catalyst, Cu-chromite, and Pt/Al₂O₃ include effects on conversion andproduct selectivity of varied reaction parameters including gas andliquid flow rates, HMF feed concentration, H₂ pressure, and/ortemperature. Table 5 shows the effect of pretreatment temperature forthe alternative Co/SiO₂ catalyst (Engelhard Co-0179). Table 6 shows theeffect of pressure for continuous flow reaction utilizing the Pt/Al₂O₃catalyst.

TABLE 5 Effect of Catalyst Pretreatment Temperature Condition # 1 13 9Reaction Temp, ° C. 362 230 150 Con Conv, % 99.9 66.9 84.3 FDM Sel 68.793.2 88.3 THF Diol Sel 29.5 1.0 4.0 Others Sel 1.7 5.8 7.7

TABLE 6 Effect of Pressure (5% Pt/Al₂O₃) 70° C., LHSV = 15 h⁻¹ 140° C.,LHSV = 30 h⁻¹ P = 500 P = 1000 P = 500 P = 1000 P = 1400 psig psig psigpsig psig HMF Conv, wt % 91.63 93.68 96.21 96.66 98.46 Sel to FDM, wt %95.10 96.06 94.22 93.33 92.82 Sel to THF Diol  0.49  0.10  0.53  0.73 1.14 Sel to Others  4.41  3.84  5.25  5.93  6.04

Example 4 Reduction of HMF with Production of FDM in a Fixed-BedContinuous Flow Reactor

A tubular reactor made of ⅜ inch stainless-steel thick-wall tubing(0.065 inch wall thickness) was utilized. 2 mL (1.11 g) of dry Pt/Al₂O₃catalyst (prepared with 5% Pt on 40-80 mesh alumina support) was reducedbefore testing at 150° C. at atmospheric pressure with a hydrogen flowof 20 mL/minute. The reactor was then cooled to 40° C. and water wasintroduced at a flow rate of 0.5 mL/min with a high pressure liquidpump.

The hydrogen gas flow was increased to approximately 120 mL/minute untilthe system pressure increased to 500 psig, at which time the hydrogenflow rate was decreased to 14 mL/minute. The temperature operating setpoint of the system was increased to 70° C. and upon achieving 70° C., a1% feed solution of HMF (optionally purged with nitrogen) was fed to thecatalyst bed at a rate of 0.5 mL/minute. At 20 minute reaction timeintervals (measured from the time feed was started) liquid samples ofthe product exiting the reactor were collected for LC analysis. LCresults for each sample taken showed 100% conversion of HMF and 95%selectivity to FDM.

After 1 hour and 40 minutes of testing the liquid feed rate of the 1%HMF solution was decreased to 0.3 mL/minute. Sampling and analysis wasrepeated at 20 minute intervals for an additional 1 hour and 40 min. Theresults indicate no observed over-reduction at this lower liquid flowrate (as apparent by the absence of THF dimethanol) and that HMFconversion remained at 100% with 95% selectivity to FDM.

As can be observed in the forgoing figures, under certain conditionsproducts other than FDM can be selectively produced from HMF withparticular catalysts. Further studies sere conducted to selectivelyproduce non-FDM products utilizing HMF, FDM or tetrahydrofurandimethanol (THFDM, THF diol) starting material.

The Co-179 catalyst in a continuous flow reactor at 70° C. resulted inhigh selectivity (>95%) to FDM (see FIGS. 28, 29 and 36), with onlymoderate selectivities to THFDM when the temperature is raised to 120°C. Referring to FIG. 57, at about 100% HMF conversion at 120° C. a THFDMselectivity of about 70% was achieved. Reduction to THFDM was incompleteand significant by-products were observed at the higher temperature.

Referring to FIG. 58, Ni/SiO₂ reduced FDM nearly quantitatively to THFDMat 70° C. However, under identical conditions utilizing HMF (FIG. 59),only 80% HMF conversion was obtained and selectivity to THFDM was about40%. When the feed was switched again to FDM, only about 20% FDMconversion was observed (FIG. 60), indicating that HMF poisons the Nicatalyst.

A staged bed (segregated catalysts in the same bed) containing ⅓ cobaltcatalyst and ⅔ nickel catalyst was tested for production of THFDM fromHMF. The HMF feed first passed through the Co catalyst which primarilyreduced the HMF to FDM, then through the Ni catalyst which primarilyreduced the FDM to THFDM. Very high HMF conversion and selectivity toTHFDM was obtained as shown in FIG. 61. The Ni catalyst appeared toremain active for THFDM production when HMF was reduced first to FDMwith the Co catalyst. HMF feed concentrations of 1%, 3%, and 6%, weretested, all giving similar conversions and selectivities.

Additional experiments were conducted utilizing the staged Co/Nicatalysts at high temperatures with either HMF or FDM feeds to examinepolyol production (FIGS. 62-70). Temperatures as high as 180° C. wereevaluated. The major product was 1,2,6-hexanetriol but yields decreasedwith increased temperatures with production of may unknown products. Onemajor by-product was identified as 2,5-hexanediol. When the feed wasTHFDM however, almost no ring-opening occurred. THFDM was quite stableup to 200° C. Ring-opened polyols therefore likely are formed via HMF orFDM, not via THFDM. FIGS. 62-70 show the results obtained under avariety of temperatures, feed (FDM vs. HMF) feed concentration and spacevelocity.

A batch-wise experiment was conducted to study the effect of organicsolvent on the catalytic hydrogenation of HMF to FDM utilizing twodifferent catalysts. Selectivity toward FDM production was compared forreactions conducted in ethanol and reactions conducted in water. Asshown in Table 7, conversion and selectivity toward FDM are lower inethanol than in water under the same reaction conditions and reactiontimes.

TABLE 7 Effect of Organic Solvent on HMF Reduction 60° C. 100° C. 500psi H₂ 950 psi H₂ Conver- Selec- Conver- Selec- Time sion tivity Timesion tivity Co/SiO₂ H₂O 4 hr 100%  96% 1 hr 98% 83% EtOH 4 hr  1% 16% 1hr  2% 49% Pt/Al₂O₃ H₂O 2 hr 94% 98% 1 hr 89% 96% EtOH 2 hr 82% 98% 1 hr53% 96%

The impact of various impurities on the hydrogenation of HMF wasinvestigated in both batch-wise and flow reactor studies. Impuritiesincluded fructose, ethyl acetate, dimethylacetamide, methyl t-butylether, methyl iso-butyl ketone, levulinic acid, formic acid, aceticacid, sodium sulfate, and N-methyl pyrrolidinone. These impurities werefound to be non-detrimental to HMF conversion within the accuracy of theexperiments.

Of particular interest were the results with fructose impurity in batchexperiments conducted between 60 and 100° C. and 500 psi for at least 2h. Both Pt(Ge)/C (Engelhard #43932) and Co/SiO₂ (Sud Chemie G62aRS)catalysts converted HMF to reduced products without reducing fructose tosorbitol or mannitol, even at high HMF conversions. FDM can be formed inhigh yield. In the absence of HMF, fructose is easily reduced underthese reaction conditions, suggesting that HMF either inhibits fructosereduction or is reduced at a faster rate. These results indicate thathighly selective reduction of HMF is possible with the HMF precursorfructose present in the feed and that fructose need not be separatedfrom the HMF solution prior to reduction.

Example 5 Reduction of HMF in the Presence of Fructose

Batch-wise experiments were conducted with an aqueous solution of 15 wt% each of HMF and fructose under 500 psi H₂ between 75 and 100° C. usingGe-promoted 5% Pt on carbon (Engelhard #43932) for at least 2 h. In asample taken at 1 h, LC and ¹³C NMR analysis showed that HMF wasconverted to FDM with good selectivity but that essentially no fructosewas converted to sorbitol or mannitol even at high HMF conversion. Onlytrace amounts of levulinic and formic acids were formed.

FIGS. 71-80 show the results of a number of batchwise HMF conversionreactions utilizing RANEY® Co-2724 (FIG. 71); 5% Pt(Ge)/C (FIG. 72); 5%Pd/C (FIG. 73); 5% Ru/C (FIG. 74); RANEY® Co-2700 (FIGS. 75-76); andRANEY® Cu (FIG. 77) catalysts. The effect of H₂ pressure wasinvestigated utilizing a 5% Pt(Ge)/C catalyst as shown in FIG. 78. FIG.79 shows the effect of temperature on HMF conversion using the Pt(Ge)/Ccatalyst, and FIG. 80 shows the effect of temperature on FDM selectivityfor the Pt(Ge)/C catalyst.

Reaction methods of the invention for selective reduction of HMF toproduce FDM and/or THF dimethanol have many advantages relative toconventional technologies. The reaction temperature of the inventivemethodology is relatively low, thereby reducing unwanted side reactionsand decomposition of reactants and/or products, and allowing increasedselectivity. The hydrogen pressure is also low resulting in reducedoperating costs. Since the solvent utilized is water rather than anorganic solvent, the methodology is relatively less expensive and moreenvironmentally friendly than many conventional processes. The reactionrates obtained through the methodology of the invention are high,allowing highly efficient continuous flow reactors to be utilized.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1-19. (canceled)
 20. A method of producing tetrahydrofuran dimethanol(THFDM), comprising: providing a continuous flow reactor having a firstcatalyst and a second catalyst; providing a feed comprisinghydroxymethyl furfural (HMF) into the reactor; contacting the feed withthe first catalyst to produce furan dimethanol (FDM); and contacting theFDM with the second catalyst to produce THFDM.
 21. The method of claim20 wherein the first catalyst is segregated from the second catalystwithin the same reactor bed.
 22. The method of claim 20 wherein the feedcomprises from about 1% to about 6% HMF.
 23. The method of claim 20wherein the THFDM is the majority product.
 24. The method of claim 20wherein the first catalyst comprises Co.
 25. The method of claim 20wherein the second catalyst comprises Ni. 26-29. (canceled)
 30. Themethod of claim 20 wherein the composition of the first catalyst isdifferent than the composition of the second catalyst.
 31. The method ofclaim 20 wherein the first catalyst comprises Co and the second catalystcomprises Ni.
 32. The method of claim 20 wherein the first catalystcomprises one or more of Ni, Co, Cu, Pd, Pt, Ru, Ir, Re and Rh.
 33. Themethod of claim 20 wherein the second catalyst comprises one or more ofNi, Ir, Co, Rh, Pt, Pd, and Ru.
 34. The method of claim 20 whereineither one or both of the first and second catalyst are maintained at atemperature below 250° C. during the contacting.